Method of and apparatus for building a sequence of tyres different from each other

ABSTRACT

A method of building a sequence of tires different from each other, includes generating a first deposition surface by a first series of consecutive circumferential sectors. The first deposition surface is selected as a function of the type of a first tire to be built. Each circumferential sector of the first series is removably coupled to a central body of a forming drum. The method further includes manufacturing at least one component of the at least one first tire by deposition of the at least one component at a radially external position to the first deposition surface of the forming drum, removing the at least one component from the forming drum and replacing each circumferential sector of the first series with a circumferential sector of a second series for generating a second deposition surface selected as a function of the type of a second tire to be built which is different from the first tire. The replacement includes uncoupling each circumferential sector of the first series from the central body and removably coupling each circumferential sector of the second series to the same central body.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase application based onPCT/IB2011/054779, filed Oct. 26, 2011, which claims the priority ofItalian Application No. MI2010A002021, filed Oct. 29, 2010, and thebenefit of U.S. Provisional Application No. 61/411,724, filed Nov. 9,2010, the content of all of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and an apparatus for buildinga sequence of tyres different from each other.

More particularly, the invention is addressed to the method andequipment used in the field of building a sequence of tyres differentfrom each other, for manufacturing components being part of the tyre inprogress of manufacture.

2. Description of the Related Art

A tyre for vehicle wheels generally comprises a carcass structureincluding at least one carcass ply having respectively opposite endflaps in engagement with respective annular anchoring structuresintegrated into the regions usually identified as “beads”, defining theradially internal circumferential edges of the tyre.

Associated with the carcass structure is a belt structure including oneor more belt layers, placed in radially superposed relationship relativeto each other and to the carcass ply, having textile or metallicreinforcing cords of crossed orientation and/or substantially parallelto the circumferential extension direction of the tyre. Applied at aradially external position is a tread band also made of elastomericmaterial like other semimanufactured products constituting the tyre.

Respective sidewalls of elastomeric material are further applied at anaxially external position, to the side surfaces of the carcassstructure, each extending from one of the side edges of the tread banduntil close to the respective annular anchoring structure to the beads.In tyres of the “tubeless” type, an airtight coating layer, usuallyreferred to as “liner” covers the inner tyre surfaces.

To the aims of the present specification and the following claims, by“reversible quick fit” it is intended a removable connection that can bequickly activated and deactivated by a restricted number of manuallyand/or automatically performed actions. Preferably, it is a deviceselectively operating between an active configuration and a passiveconfiguration, more preferably following the action of moving twoelements to be connected close to each other.

To the aims of the present specification and the following claims, by“snap-fit device” it is intended a device that is intrinsicallystimulated to take an active configuration in which coupling of two ormore components can take place. Preferably, it is a device that iselastically stimulated to take an active configuration and morepreferably that is suitable to at least move from a passiveconfiguration to an active configuration following the action of movingtwo elements to be connected close to each other.

To the aims of the present specification and the following claims, theterm “strip-like element” means an elongated manufactured product cut tosize, which has a cross-section outline of flattened conformation andcomprises one or more cords of textile and/or metallic materialextending parallel to the longitudinal extension of the strip-likeelement itself and embedded in, or at least partly coated with at leastone layer of elastomeric material.

To the aims of the present specification and the following claims, theterm “component” of a tyre is understood as indicating the assembly ofone or more components or any portion or combination of same, adapted toperform a function in the tyre, selected for example from: liner,under-liner, carcass ply/plies, under-belt insert, belt strips bothcrossed with each other and at zero degrees, attachment skim coat forthe tread band, tread band, bead core, bead filler, textile reinforcinginserts made of metal or of elastomeric material alone, abrasion-proofinsert, sidewall inserts.

SUMMARY OF THE INVENTION

The Applicant could observe that on a forming drum externally having asubstantially cylindrical deposition surface, a plurality of strip-likeelements can be applied which are disposed adjacent to each other so asto form at least one first annular reinforcing layer on the forming drumitself, set to a first work diameter in which each of the appliedstrip-like elements on the deposition surface subtends an arc of acircumference of a width equal to a whole sub-multiple of the overallcircumferential extension of the deposition surface itself. Adjustingdevices operating on the forming drum can subsequently carry outexpansion of the drum to a second work diameter greater that the firstwork diameter, while maintaining the deposition surface substantiallycylindrical. The Applicant has also observed that such a forming drumcan comprise consecutive circumferential sectors, radially movable uponcommand of the adjusting devices. Each of the circumferential sectorscan have comb-shaped end portions operatively engaging each in a matingcomb-shaped end portion carried by a circumferentially adjacentcircumferential sector.

The Applicant has observed that tendentially each tyre size requires aspecific forming drum for formation of one or more belt layers or acarcass structure.

While having ascertained the possibility of using the same type offorming drum for two or more tyre sizes, the Applicant has howevernoticed that a process and an apparatus as above described would requiremanagement of some typologies of forming drums for which a specificwarehouse is necessary.

The Applicant has perceived the necessity to optimise the management ofthe forming drums without being obliged to provide a specific warehouseof big sizes for forming drums having shapes and/or sizes different fromeach other, while ensuring the possibility of selecting the forming drumas a function of the size of the tyre to be made.

The Applicant has found that by providing a plurality of forming drumshaving a single central body to which it is possible to couple a seriesof circumferential sectors selected from at least one first and onesecond series of circumferential sectors depending on the size of thetyre to be manufactured, the warehouse related to the forming drums canbe restricted to the only series of circumferential sectors, and therange of forming drums from which it is possible to make a selection canbe wider.

More particularly, in accordance with a first aspect, the inventionrelates to a method of building a sequence of tyres different from eachother, comprising:

-   -   generating a first deposition surface by a first series of        consecutive circumferential sectors, said first deposition        surface being selected as a function of the type of a first tyre        to be built; each circumferential sector of the first series        being removably coupled to a central body of a forming drum;    -   manufacturing at least one component of said at least one first        tyre by deposition of said at least one component at a radially        external position to said first deposition surface of the        forming drum;    -   removing said at least one component from the forming drum;    -   replacing each circumferential sector of the first series with a        circumferential sector of a second series for generating a        second deposition surface selected as a function of the type of        a second tyre to be built which is different from said first        tyre;    -   said replacement comprising uncoupling each circumferential        sector of the first series from the central body and removably        coupling each circumferential sector of the second series to the        same central body.

The Applicant has ascertained that greater production flexibility isthus advantageously obtained as a wide range of series ofcircumferential sectors and therefore of forming drums is madeavailable, so that it is restricted the room that is not directlyintended for production, such as that taken up by a warehouse for theforming drums.

In accordance with a second aspect, the invention relates to anapparatus for building a sequence of tyres different from each other,comprising:

-   -   at least one central body of a forming drum,    -   at least one first series of circumferential sectors in which        each circumferential sector of said first series is adapted to        be removably coupled to said central body so as to generate a        first deposition surface;    -   at least one second series of circumferential sectors in which        each circumferential sector of said second series is adapted to        be removably coupled to said central body so as to generate a        second deposition surface;    -   said first deposition surface being selected as a function of        the type of a first tyre to be built and said second deposition        surface being selected as a function of the type of a second        tyre to be built which is different from said first tyre.

This apparatus helps in making available a wide range of series ofcircumferential sectors and therefore of forming drums.

The present invention, in accordance with one of the aforesaid aspects,can have one or more of the preferred features hereinafter described.

In accordance with a possible embodiment, each circumferential sector isremovably coupled to said central body by activating at least onereversible quick-fit device.

This enables the time for replacement of the circular sectors to bereduced, thereby being reduced the idle time in the work cycle.

In a possible embodiment, replacement of each circumferential sector ofthe first series with a circumferential sector of the second seriescomprises uncoupling each circumferential sector of the first seriesfrom the central body by deactivating at least one reversible quick-fitdevice.

Preferably, replacement of each circumferential sector of the firstseries with a circumferential sector of the second series comprisesuncoupling each circumferential sector of the first series from thecentral body by deactivating at least one reversible quick-fit devicefor each circumferential sector. This helps in simplifying andshortening the time of uncoupling the circumferential sectors of thefirst series on changing of the tyre size.

According to a possible embodiment, replacement of each circumferentialsector of the first series with a circumferential sector of the secondseries comprises coupling each circumferential sector of the secondseries to the central body by activating said at least one reversiblequick-fit device.

According to a further possible embodiment, replacement of eachcircumferential sector of the first series with a circumferential sectorof the second series comprises coupling each circumferential sector ofthe second series to the central body by activating said at least onereversible quick-fit device for each circumferential sector. In thismanner the time required for coupling the circumferential sectors of thesecond series, on changing of the tyre size, is simplified andshortened.

In a further embodiment, the reversible quick-fit device is a snap-fitdevice. Use of a snap-fit device helps in simplifying and thereforereducing the time in particular required for coupling thecircumferential sectors to the central body. In addition, it helps inmaking coupling and uncoupling of the circumferential sectorsindependent of the operating modes adopted by an operator.

Preferably, replacement of each circumferential sector of the firstseries with a circumferential sector of the second series comprisesdeactivating and activating the same snap-fit device for eachcircumferential sector. This helps in optimising the number ofcomponents coming into play and therefore to make uniform the actions tobe carried out in the replacement step, and the obtained result.

According to a further embodiment, the reversible quick-fit device isactivated for coupling a circumferential sector to said central body byrelatively moving said circumferential sector close to said central bodyin a radial direction.

Preferably, the reversible quick-fit device is deactivated foruncoupling a circumferential sector from said central body by relativelymoving a release element in a radial direction close to saidcircumferential sector coupled to said central body. The radialapproaching movement helps in restricting the relative stroke between acircumferential sector, the central body and possibly the releaseelement.

In accordance with a possible embodiment, the radial position of thecircumferential sectors coupled to the central body is modified beforemanufacturing at least one component of said at least one first tyre.Thus the position in which the circumferential sectors are coupled isoptimised, this position being independent of the position in which saidtyre component is manufactured.

In accordance with a further embodiment, modifying the radial positionof the circumferential sectors coupled to the central body comprisestranslating the circumferential sectors from a first diameter in whichsaid first deposition surface is generated, to a second diameter greaterthan said first diameter. In this way, coupling of the circumferentialsectors is simplified by selecting a compact radial position relative tothe position in which said tyre component is manufactured.

In accordance with a further embodiment, the radial position of thecircumferential sectors coupled to the central body is modified beforereplacing each circumferential sector of the first series with acircumferential sector of the second series. Thus, the position in whichthe circumferential sectors are replaced is optimised as it isindependent of the position in which said tyre component ismanufactured.

According to a possible embodiment, manufacturing said at least onecomponent of said at least one first tyre by deposition of said at leastone component at a position radially external to said first depositionsurface of the forming drum is carried out in correspondence of saidsecond diameter.

Preferably, modifying the radial position of the circumferential sectorscoupled to the central body before replacing each circumferential sectorof the first series with a circumferential sector of the second seriescomprises translating the circumferential sectors from said seconddiameter to a third diameter smaller than said second diameter. In thisway, replacement of the circumferential sectors is simplified byselecting a compact radial position relative to the position in whichsaid tyre component is manufactured.

Preferably, said first diameter and third diameter are substantiallyidentical. In this manner, a single coupling and uncoupling position forthe circumferential sectors is defined.

In accordance with a possible embodiment, manufacturing said at leastone component of said at least one first tyre comprises manufacturing atleast one first belt layer.

In particular, manufacturing said at least one component of said atleast one first tyre comprises applying a plurality of strip-likeelements on said forming drum, which strip-like elements are disposed ina mutually approached relationship according to the circumferentialextension of said forming drum for making at least one first belt layer.

Preferably, manufacturing said at least one component of said at leastone first tyre comprises making at least one crown structure includingat least one first belt layer and a tread band.

According to a possible embodiment, each circumferential sector isadapted to be removably coupled to said central body by activating atleast one reversible quick-fit device.

Preferably, each circumferential sector is adapted to be uncoupled fromthe central body by deactivating at least one reversible quick-fitdevice. The presence of a reversible quick-fit device helps in reducingthe time for replacement of the circular sectors and in simplifyingcarrying out of this operation.

According to a possible embodiment, each circumferential sector isadapted to be removably coupled to said central body or uncoupled fromsaid central body by activating or respectively deactivating at leastone reversible quick-fit device for each circumferential sector. Thissolution helps in making uniform each sector of the drum and thereforethe operations to be carried out for coupling or uncoupling it to andfrom the central body.

Preferably, the same reversible quick-fit device is adapted toselectively couple and uncouple a circumferential sector of the firstseries to and from the central body and a circumferential sector of thesecond series to and from the same central body. This helps inoptimising the number and type of components of the apparatus.

Preferably, the reversible quick-fit device is adapted to be activatedfor coupling a circumferential sector to said central body by movingsaid circumferential sector and central body in a radial directiontowards and close to each other.

According to a possible embodiment, the reversible quick-fit device is asnap-fit device. In this way, replacement of the circumferential sectorsis simplified.

Preferably, at least one release element is adapted to be relativelymoved, in a radial direction, close to said circumferential sectorcoupled to said central body so as to deactivate said snap-fit deviceand uncouple the circumferential sector from said central body.

Preferably, provision is made for a snap-fit device for eachcircumferential sector.

In accordance with a possible embodiment, a snap-fit device comprises atleast two portions distributed along an axial direction of said centralbody. In this manner, this helps in stabilising coupling between thecircumferential sector and the central body.

Preferably, at least one portion of the snap-fit device is disposed atan end portion of a circumferential sector in a coupled configurationwith the central body. Thus possible overhanging stretches of acircumferential sector are advantageously limited.

In accordance with a possible embodiment, the snap-fit device comprisesat least one movable hooking element adapted to take at least one activeposition at which said snap-fit element is activated and a passiveposition at which said snap-fit element is deactivated. Thus coupling ofthe circumferential sectors is made particularly efficient andreplacement of same is simplified.

Preferably, said movable hooking element is constantly biased to theactive position. Thus the operations to be carried out in coupling andreplacing the circumferential sectors are simplified.

In accordance with a possible embodiment, said movable hooking elementis adapted to move in a substantially axial direction of the centralbody. Thus an efficient constraint to the radial forces to which thecircular sectors are submitted is provided.

In a further embodiment, said movable hooking element is associated withthe central body. As a result, the number of components of the apparatusis limited.

According to a possible embodiment, the snap-fit device comprises atleast one fixed hooking element including a housing seat adapted toreceive said movable hooking element in the active position of themovable hooking element itself. Coupling of the circumferential sectorsis therefore made particularly efficient and replacement of same issimplified.

Preferably, the fixed hooking element comprises at least one rampadapted to interact with the movable hooking element to producedisplacement thereof from the active position to the passive positionand cause introduction of same into said housing seat, activating saidsnap-fit device. Coupling is therefore simplified as it is sufficient tomove a circumferential sector close to the central body.

In accordance with a possible embodiment, said snap-fit device comprisesat least one release element.

Preferably, said fixed hooking element comprises a slide seat for saidrelease element, said slide seat being in communication with saidhousing seat.

Preferably, said movable hooking element is adapted to end in said slideseat in the active position of the movable hooking element itself. Thisrepresents a help in simplifying the uncoupling operation, due to theguide supplied by the slide seat.

Preferably, said movable hooking element and/or at least one portion ofa confining wall of the housing seat comprises a shaped outline adaptedto allow relative moving apart of a circumferential sector associatedwith the release element relative to the central body. This represents ahelp in limiting the operations required during the step of replacingthe circumferential sectors.

According to a possible embodiment, said fixed hooking element isassociated with a circumferential sector. Thus the number of componentsof the apparatus is advantageously limited.

Further features and advantages will become more apparent from thedetailed description of a preferred but not exclusive embodiment of amethod and an apparatus for building a sequence of tyres different fromeach other, according to the present invention.

BRIEF DESCRIPTION THE DRAWINGS

This description will be set out hereinafter with reference to theaccompanying drawings, given by way of non-limiting example, in which:

FIG. 1 diagrammatically shows a top view of an apparatus for building asequence of tyres different from each other, made in accordance with thepresent invention;

FIG. 2 diagrammatically shows a fragmentary diametrical section view ofa tyre that can be manufactured by the method and apparatus being theobject of the present invention;

FIG. 3 is a diagrammatic perspective view partly interrupted of aforming drum that is part of the apparatus being the object of thepresent invention;

FIG. 4 diagrammatically shows a diametrical section of a portion of theforming drum corresponding to a circumferential sector associated with aportion of a central body;

FIGS. 5 and 6 diagrammatically show a diametrical section of a portionof the forming drum in a first and second operating conditions,respectively.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the drawings, generally denoted at 1 is an apparatusfor building a sequence of tyres different from each other, designed toput into practice a method according to the present invention.

Apparatus 1 is designed to manufacture tyres 2 (FIG. 2) essentiallycomprising a carcass structure 3 having at least one carcass ply 4 and acrown structure associated with said carcass structure 3 at a radiallyexternal position.

A layer of airtight elastomeric material or a so-called liner 5 can beapplied internally of the carcass ply/plies 4. Two annular anchoringstructures 6 each including a so-called bead core 6 a carrying anelastomeric filler 6 b at a radially external position are in engagementwith respective end flaps 4 a of the carcass ply/plies 4. The annularanchoring structures 6 are integrated in the vicinity of regions usuallyidentified as “beads” 7, at which usually engagement between tyre 2 anda respective mounting rim takes place.

Preferably, the crown structure comprises at least one belt structurehaving a belt layer or strip. More preferably, the crown structurecomprises a belt structure having at least one belt layer or strip and atread band.

In the example shown in FIG. 2, a belt structure 8 comprising two beltlayers 8 a, 8 b is circumferentially applied around the carcassply/plies 4. A tread band 9 is circumferentially superposed on said beltstructure 8.

So-called “under-belt inserts” 10 can be associated with the beltstructure 8 being each disposed between the carcass ply/plies 4 and oneof the axially opposite end edges of the belt structure 8. In additionor as an alternative to the under-belt inserts 10, annular inserts ofelastomeric material and/or comprising cords or other reinforcingelements can be radially superposed at least on the axially opposite endedges of the belt structure 8, and/or interposed between the belt layers8 a, 8 b, at least at said end edges.

Two sidewalls 11, extending each from the corresponding bead 7 to acorresponding side edge of the tread band 9, are applied to the carcassply/plies 4 at laterally opposite positions.

In building the carcass structure and crown structure, respectiveforming drums are used that are defined as primary drum and respectivelyauxiliary drum, for example.

Generally, a forming drum can externally have a deposition surface ofsubstantially cylindrical conformation, made up of a plurality ofcircumferential sectors consecutively disposed around a geometricsymmetry axis of the forming drum. These elements will be describedbelow with reference to FIG. 3 and the following figures related to anauxiliary drum.

To the aims of the present invention by the expression “substantiallycylindrical” drum it is intended a drum corresponding to a solid ofrevolution defined by a generatrix having rectilinear extension orarched outline.

With reference to FIG. 1, apparatus 1 comprises a carcass-buildingstation, generally identified with reference numeral 12, for example.

In the carcass-building station 12 the carcass ply/plies 4 can be madestarting from a manufactured article in the form of a continuous strip,consisting of cords of textile or metallic material, disposed parallelto each other in a matrix of elastomeric material. Preferably saidcarcass ply/plies 4 are made by deposition on a forming drum, inparticular a so-called primary drum, not shown, of a plurality ofstrip-like elements disposed in mutually adjacent relationship accordingto the circumferential extension of the forming drum.

In the carcass-building station the primary drum can be operativelysupported by at least one chuck, a robotized arm, or other deviceenabling said drum to be driven in rotation, if necessary, and/or to besuitably moved during application of the components of the carcassstructure 3.

More particularly, the primary drum is adapted to first receive liner 5,if any, preferably made by spiraling of a continuous elongated elementof elastomeric material, and subsequently the carcass ply/plies 4 so asto form a cylindrical sleeve on the opposite end flaps of which theannular anchoring structures 6 are subsequently fitted. Turning-up ofthe end flaps 4 a of the carcass ply/plies 4 around the annularanchoring structures 6 can be subsequently carried out. Application ofthe sidewalls 11 on the primary drum can be further provided, preferablyby spiraling of a continuous elongated element thereon, which operationis preferably carried out after application of the carcass ply/plies 4.

The primary drum with which the carcass structure 3 made in the form ofa cylindrical sleeve is associated can be transferred by a firsttransfer member 13 to an assembling and shaping station 14.

With reference to FIG. 1, apparatus 1 further comprises acrown-structure building station generally denoted at 15, for example.

Each of the belt layers 8 a, 8 b of the crown structure can be made bywinding a segment obtained from a semimanufactured product in the formof a continuous strip on a forming drum (in particular, a so-calledauxiliary drum 16, illustrated in more detail in FIG. 3 and in thefollowing figures). Preferably, each belt layer is made by deposition ofa plurality of strip-like elements on said auxiliary drum 16, whichstrip-like elements are disposed in mutually approached relationshipaccording to the circumferential extension of the auxiliary drum 16.

For completing said crown structure, a tread band 9 is preferably madeon said belt layers thus formed on the auxiliary drum 16, by spiralingof at least one continuous elongated element of elastomeric material ata radially external position relative to said belt layers. The crownstructure thus formed is subsequently picked up from the auxiliary drum16 to be coupled to the carcass structure 3 preferably disposed on theprimary drum inside the assembling and shaping station 14.

Alternatively or in association with application of the same on theprimary drum, the tyre sidewalls 11 can be made in the continuation ofthe axially opposite edges of the tread band 9. Preferably thisoperation takes place by spiraling at least one continuous elongatedelement of elastomeric material on the auxiliary drum 16 carrying thecrown structure being formed.

A second transfer member 17 movable between the crown-structure buildingstation 15 (in particular the auxiliary drum 16) and the assembling andshaping station 14 carries out transfer of the crown structure onto thecarcass structure 3 preferably supported by the primary drum.

When the crown structure is in a centred position relative to thecarcass structure 3, the carcass structure 3 is shaped into a toroidalconfiguration, in a manner known by itself. The consequent radialexpansion of the carcass ply/plies 4 makes the latter adhere against theinner surface of the crown structure.

Tyre 2 thus built is adapted to be removed from the assembling andshaping station 14 by a third transfer member 18 for example, to besubmitted to a curing and moulding treatment in a curing and mouldingstation 19, and/or to other working operations provided in the workcycle.

According to an embodiment of the present invention, shown in FIG. 3 forexample, apparatus 1 for building a sequence of tyres different fromeach other comprises at least one central body 20 of a forming drum, inparticular an auxiliary drum, and at least one first series ofcircumferential sectors 21. A circumferential sector 21 of the firstseries is adapted to be removably coupled to the central body 20 forgenerating a first deposition surface 22. Apparatus 1 further comprisesat least one second series of circumferential sectors, herein not shownbut similar to the sectors of the first series, in which acircumferential sector of the second series is adapted to be removablycoupled to the central body 20 so as to generate a second depositionsurface different from the first deposition surface.

The following description related to each circumferential sector 21 ofthe first series, in particular with reference to the conformation ofthe reversible quick-fit device, is also valid for the circumferentialsectors of other series, in particular for the circumferential sectorsof the second series.

FIG. 3 and the following ones are hereinafter described with referenceto the first series of circumferential sectors 21.

The first deposition surface is selected as a function of the type of afirst tyre to be built and the second deposition surface is selected asa function of the type of a second tyre to be built that is differentfrom the first tyre.

Hereinafter the invention will be described with reference tomanufacture of the crown structure, in which the forming drum is theauxiliary drum 16. In FIG. 3 a geometric symmetry axis of the auxiliarydrum 16 defining an axial direction has been denoted by “X”.

A sector-changing station 23 is preferably interlocked with thecrown-structure building station 15 for providing the forming drum, inparticular the auxiliary drum 16 provided with the deposition surfacesuitable for the type of tyre being built. A fourth transfer member 24removes the auxiliary drum from the sector-changing station 23 andtransfers it to the crown-structure building station 15.

The sector-changing station 23 comprises at least one central body 20and at least two series of circumferential sectors; in particular asmany series of circumferential sectors as the types of tyres to be builtcan be provided.

In accordance with the method of the invention, inside thesector-changing station 23 shown in FIG. 1 the first deposition surface22 can be generated by the first series of consecutive circumferentialsectors 21.

In particular each circumferential sector 21 of the first series isremovably coupled to the central body of the auxiliary drum 16 thusgenerating the first deposition surface 22.

The auxiliary drum 16 is then transferred to the crown-structurebuilding station 15 so as to make at least one component of the firsttyre by deposition of such a component on the first deposition surface22. With reference to the example shown, the auxiliary drum 16 istransferred to the crown-structure building station 15 for making acrown structure. Preferably said at least one component of the firsttyre is obtained by applying a plurality of strip-like elements at aradially external position to the first deposition surface 22 of theauxiliary drum, which strip-like elements are disposed in mutuallyapproached relationship according to the circumferential extension ofthe auxiliary drum 16 so as to make a first belt layer, for example.

The crown structure, when building of same has been completed, isremoved from the auxiliary drum and transferred to the assembling andshaping station 14 for example, as previously described.

On passing from building of the first type of tyre to building of thesecond type of tyre that is different from the first one, the auxiliarydrum 16 is transferred to the sector-changing station 23 before beingtransferred again to the building station of the crown structure 15, forreplacing each circumferential sector 21 of the first series with acircumferential sector of the second series so as to generate the seconddeposition surface selected as a function of the type of the second tyreto be built that is different from the first tyre.

Replacement of the circumferential sectors contemplates uncoupling ofeach circumferential sector 21 of the first series from the central body20 and removable coupling of each circumferential sector of the secondseries to the same central body 20.

With reference to the method of building a sequence of tyres differentfrom each other, replacement of each circumferential sector 21 of thefirst series with a circumferential sector of the second seriescontemplates uncoupling of each circumferential sector 21 of the firstseries from the central body 20 by deactivating at least one reversiblequick-fit device 25. In particular, replacement of each circumferentialsector 21 of the first series with a circumferential sector of thesecond series contemplates uncoupling of each circumferential sector 21of the first series from the central body 20 by deactivating at leastone reversible quick-fit device for each circumferential sector.

In addition, replacement of each circumferential sector 21 of the firstseries with a circumferential sector of the second series comprisescoupling each circumferential sector of the second series to the centralbody 20 by activating the reversible quick-fit device 25. In particularreplacement of each circumferential sector 21 of the first series with acircumferential sector of the second series comprises coupling eachcircumferential sector of the second series to the central body 20 byactivating at least one reversible quick-fit device 25 for eachcircumferential sector.

With reference to the example shown in the figures, the same reversiblequick-fit device 25 is suitable for selectively coupling and uncouplinga circumferential sector 21 of the first series to and from the centralbody 20 and a circumferential sector of the second series to and fromthe same central body 20.

With reference for example to FIG. 3 and the following figures, thereversible quick-fit device 25 is activated for coupling acircumferential sector to the central body 20 by relatively moving thecircumferential sector close to the central body 20 in a radialdirection. In the example shown, each circumferential sector is radiallymoved close to the central body. In addition, the reversible quick-fitdevice 25 is deactivated for uncoupling a circumferential sector fromthe central body 20 by relatively moving a release element 26 in aradial direction close to said circumferential sector coupled to saidcentral body 20.

With reference for example to FIG. 3 and the following figures, thereversible quick-fit device 25 is a snap-fit device. In accordance withthe preceding description, at least one release element 26 (FIG. 6) isadapted to be relatively moved close in the radial direction to thecircumferential sector coupled to the central body for deactivating thesnap-fit device and uncoupling the circumferential sector from thecentral body.

In particular, according to the example shown, the auxiliary drum 16belonging to apparatus 1 comprises a snap-fit device for eachcircumferential sector.

With reference to FIG. 3 and the following figures, the snap-fit devicecomprises at least two portions 27 distributed along an axial directionof the central body 20. In particular at least one portion 27 of thesnap-fit device is disposed at an end portion of a circumferentialsector in the configuration coupled to the central body. In the exampleshown the two portions 27 of the snap-fit device are disposed atopposite end portions respectively of the circumferential sector in theconfiguration coupled to the central body.

FIGS. 5-6 show a portion 27 of the snap-fit device comprising at leastone movable hooking element 28 adapted to take at least one activeposition (FIG. 5) at which the snap-fit device is activated and apassive position at which the snap-fit devices is deactivated (FIG. 6).Preferably, the movable hooking element 28 is constantly pushed to theactive position by at least one spring element 29, for example.

According to the example shown, the movable hooking element 28 isadapted to move in a substantially axial direction of the central body.This direction is parallel to the geometric axis X.

Advantageously, the movable hooking element 28 is associated with thecentral body 20. In particular, denoted at 30 is an arm of the centralbody 20 on which a circumferential sector is mounted, said arm 30comprising a seat 31 in which the movable hooking element 28 is housed.Seat 31 preferably extends along the axial direction defining thedirection along which the movable hooking element 28 moves.

Denoted at 32 is an opening formed in the arm 30 of the central body 20for receiving a fixed hooking element 33 to be described in detail inthe following. Opening 32 is a through opening for example and itextends in a radial direction of the central body 20. The opening 32 andseat 31 mutually intersect at a free end of the movable hooking element28.

FIGS. 5-6 show a portion 27 of the snap-fit device further comprising atleast one fixed hooking element 33 associated with a circumferentialsector, for example. In particular, the fixed hooking element 33 has apin structure extending in the radial direction from a radially internalsurface of the circumferential sector. By the term “radially internalsurface” it is intended a surface facing the central body in theassembled configuration of the auxiliary drum.

The fixed hooking element 33 is adapted to be received in the opening 32of arm 30 and comprises a housing seat 34 adapted to receive the movablehooking element 28 in the active position of the movable hooking elementitself.

With reference to FIGS. 5-6, the fixed hooking element 33 comprises atleast one ramp 35 adapted to interact with the movable hooking element28 to cause shifting of same from the active position to the passiveposition and produce fitting thereof into the housing seat 34 activatingthe snap-fit device. FIG. 5 shows a portion of the circumferentialsector and the central body corresponding to the snap-fit device, inwhich the fixed hooking element 33 is inserted in the opening 32 and themovable hooking element 28 is inserted in the housing seat 34.

As shown in the figures, the snap-fit device comprises at least onerelease element 26 preferably provided with a ramp 26 a for interactingwith the movable hooking element 28. In particular, the fixed hookingelement 33 comprises a slide seat 36 for the release element 26. Theslide seat 36 is in communication with the housing seat 34, and themovable hooking element 28 is adapted to end into the slide seat 36 inthe active position of the movable hooking element itself. Inparticular, the slide seat 36 extends along a radial direction of thecentral body forming a preferably cylindrical and internally hollow sidewall 37. The housing seat 34 is obtained through an opening of the sidewall 37 being confined by a bounding wall 38. The bounding wall 38further forms a constraint against which the movable hooking element inthe active position abuts, for locking the circumferential sector on thecentral body.

In accordance with the embodiment shown, the movable hooking element 28and/or at least one portion of the bounding wall 38 of the housing seat34 comprises a shaped outline 39 adapted to enable relative moving apartof a circumferential sector associated with the release element 26relative to the central body 20 when the release element 26 is insertedin the slide seat 36.

As previously said, FIGS. 5-6 show a portion 27 of the snap-fit device.Preferably the other portion is a mirror image relative to a medianplane perpendicular to the symmetry axis X. In particular, eachcircumferential sector is carried by at least one or, as shown in FIG.3, a pair of radial arms 30 placed in the vicinity of respective axiallyopposite sides of the auxiliary drum. Arms 30 are operatively inengagement with radial-positioning adjusting devices for the sectorsthemselves, not described in detail. These adjusting devices are adaptedto simultaneously cause translation of the circumferential sectors in adirection radial to the geometric axis X of the auxiliary drum 16, so asto give rise to a variation in the diametrical sizes of the drum itself,starting from a minimum diameter at which the circumferential sectorscan, for example, mutually act in abutment by means of respectivecircumferential shoulders they are provided with at the depositionsurface, so as to give the same a continuous course.

The circumferential shoulders of each circumferential sector arepreferably defined at respective comb-shaped end portions 40 each ofwhich is operatively in engagement with a mating comb-shaped end portion40 carried by a circumferentially adjacent circumferential sector. Inthis way, the deposition surface advantageously keeps its substantiallycylindrical conformation and a substantially continuous extension, i.e.without important discontinuities, also following a radial expansion ofthe forming drum upon the action of the adjusting devices.

The adjusting devices preferably comprise at least one or, as shown inFIG. 3, a pair of spiral-shaped cams 41 operatively engaging thecircumferential sectors, at respective sliders 42 carried each by one ofarms 30. The spiral-shaped cams 41 each engage the sliders 42 of arms 30disposed on the same side of the auxiliary drum 16 and are fastened to agrip shank 43 coaxial with the geometric axis X and drivable in rotationby a handling device that can be removably connected to the drum.

At least one or, as shown, a pair of guide flanges 44 support thecircumferential sectors radially guiding them relative to the geometricaxis X by means of guide seats 45 slidably crossed by the respectiveradial arms 30. The guide flanges 44 are rotatably supported by the gripshank 43 through bearings.

Preferably, at least one robotized arm is suitable to operatively engagethe grip shank 43 for conveniently supporting and moving the auxiliarydrum 16 in the sector-changing station 23 and the crown-structurebuilding station 15.

In particular, provision is made for modifying the radial position ofthe circumferential sectors coupled to the central body beforemanufacturing the first component of the crown structure of the tyrebeing processed. To this aim, the robotized arm operates on theadjusting devices as previously described, for example. In greaterdetail, the radial position of the circumferential sectors 21 coupled tothe central body 20 is modified through translation of thecircumferential sectors 21 from a first diameter in which the firstdeposition surface is generated to a second diameter greater than thefirst diameter. Preferably, the auxiliary drum 16 set to the seconddiameter is adapted to manufacture a first component of the crownstructure of the tyre being processed, a pair of under-belt inserts orat least one belt layer, for example.

In addition, provision is made for modifying the radial position of thecircumferential sectors 21 coupled to the central body 20 beforereplacing each circumferential sector 21 of the first series with acircumferential sector of the second series. In this case, when thecrown structure has been made by deposition carried out on thedeposition surface of the auxiliary drum at the second diameter, theradial position of the circumferential sectors 21 coupled to the centralbody 20 is subsequently modified before replacing each circumferentialsector 21 of the first series with a circumferential sector of thesecond series. In particular, the circumferential sectors 21 of thefirst series are submitted to translation from the second diameter to athird diameter smaller than the second diameter.

Preferably, the first diameter and third diameter are substantiallyidentical. In other words, mounting and dismantling of thecircumferential sectors takes place in correspondence of the samediameter of the auxiliary drum 16.

The above described apparatus and method refer to a crown-structurebuilding station 15 with reference to the fact that the manufacturedcrown structure also comprises the tread band. Alternatively, thecrown-structure building station 15 can be replaced with a buildingstation concerning one or more belt layers, should the tread band bemanufactured subsequently.

In the example shown, two different transfer members have been providedwhich operate between the crown-structure building station 15 and theassembling and shaping station 14 and between the sector-changingstation 23 and the crown-structure building station 15. Alternatively, asingle transfer member can perform both functions.

The invention claimed is:
 1. A method of building a sequence of tyresdifferent from each other, comprising: generating a first depositionsurface by a first series of consecutive circumferential sectors, saidfirst deposition surface being selected as a function of a type of afirst tyre to be built; each circumferential sector of the first seriesbeing removably coupled to a central body of a forming drum;manufacturing at least one component of said first tyre by deposition ofsaid at least one component at a radially external position to saidfirst deposition surface of the forming drum; removing said at least onecomponent from the forming drum; and replacing each circumferentialsector of the first series with a circumferential sector of a secondseries for generating a second deposition surface selected as a functionof a type of a second tyre to be built which is different from saidfirst tyre; wherein said replacing comprises translating eachcircumferential sector of the first series radially inward to an innerdiameter position, and while each circumferential sector is positionedat the inner diameter position, uncoupling each circumferential sectorof the first series from the central body, and at the inner diameterposition, removably coupling each circumferential sector of the secondseries to a same central body.
 2. The method as claimed in claim 1,wherein each circumferential sector is removably coupled to said centralbody by activating at least one reversible quick-fit device.
 3. Themethod as claimed in claim 2, wherein said reversible quick-fit deviceis a snap-fit device.
 4. The method as claimed in claim 3, wherein saidreplacing of each circumferential sector of the first series with acircumferential sector of the second series comprises deactivating andactivating a same snap-fit device for each circumferential sector. 5.The method as claimed in claim 2, wherein the reversible quick-fitdevice is activated for coupling a circumferential sector to saidcentral body by relatively moving said circumferential sector close tosaid central body in a radial direction.
 6. The method as claimed inclaim 2, wherein the reversible quick-fit device is deactivated foruncoupling a circumferential sector from said central body by relativelymoving a release element in a radial direction close to saidcircumferential sector coupled to said central body.
 7. The method asclaimed in claim 1, wherein said replacing of each circumferentialsector of the first series with a circumferential sector of the secondseries comprises uncoupling each circumferential sector of the firstseries from the central body by deactivating at least one reversiblequick-fit device.
 8. The method as claimed in claim 7, wherein saidreplacing of each circumferential sector of the first series with acircumferential sector of the second series comprises coupling eachcircumferential sector of the second series to the central body byactivating said at least one reversible quick-fit device.
 9. The methodas claimed in claim 7, wherein said replacing of each circumferentialsector of the first series with a circumferential sector of the secondseries comprises coupling each circumferential sector of the secondseries to the central body by activating said at least one reversiblequick-fit device for each circumferential sector.
 10. The method asclaimed in claim 1, wherein said replacing of each circumferentialsector of the first series with a circumferential sector of the secondseries comprises uncoupling each circumferential sector of the firstseries from the central body by deactivating at least one reversiblequick-fit device for each circumferential sector.
 11. The method asclaimed in claim 1, comprising: modifying the radial position of thecircumferential sectors coupled to the central body before manufacturingat least one component of said first tyre.
 12. The method as claimed inclaim 11, wherein modifying the radial position of the circumferentialsectors coupled to the central body comprises translating thecircumferential sectors from a first diameter in which said firstdeposition surface is generated to a second diameter greater than saidfirst diameter.
 13. The method as claimed in claim 12, wherein:manufacturing said at least one component of said first tyre bydeposition of said at least one component at a position radiallyexternal to said first deposition surface of the forming drum is carriedout in correspondence with said second diameter.
 14. The method asclaimed in claim 1, wherein the inner diameter is smaller than saidsecond diameter.
 15. The method as claimed in claim 14, wherein saidfirst diameter and the inner diameter are substantially identical. 16.The method as claimed in claim 1, wherein: manufacturing said at leastone component of said first tyre comprises manufacturing at least onefirst belt layer.
 17. The method as claimed in claim 1, wherein:manufacturing said at least one component of said first tyre comprisesapplying a plurality of strip-like elements on said forming drum, saidstrip-like elements being disposed in a mutually approached relationshipaccording to the circumferential extension of said forming drum formaking at least one first belt layer.
 18. The method as claimed in claim1, wherein: manufacturing said at least one component of said first tyrecomprises making at least one crown structure comprising at least onefirst belt layer and a tread band.
 19. An apparatus for building asequence of tyres different from each other, comprising: at least onecentral body of a forming drum; at least one first series ofcircumferential sectors in which each circumferential sector of saidfirst series is adapted to be removably coupled to said central body soas to generate a first deposition surface; and at least one secondseries of circumferential sectors in which each circumferential sectorof said second series is adapted to be removably coupled to said centralbody so as to generate a second deposition surface; wherein said firstdeposition surface is selected as a function of a type of a first tyreto be bunt and said second deposition surface is selected as a functionof a type of a second tyre to be bunt which is different from said firsttyre; wherein each circumferential sector of the first series isradially translatable between an inner diameter position and an outerdiameter position, and further adapted to be uncoupled from the centralbody at the inner diameter position; and wherein each circumferentialsector of the second series is further adapted to be coupled to thecentral body at the inner diameter position.
 20. The apparatus asclaimed in claim 19, wherein each circumferential sector is adapted tobe removably coupled to said central body by activating at least onereversible quick-fit device.
 21. The apparatus as claimed in claim 20,wherein a same reversible quick-fit device is adapted to selectivelycouple and uncouple a circumferential sector of the first series to andfrom the central body and a circumferential sector of the second seriesto and from a same central body.
 22. The apparatus as claimed in claim20, wherein the reversible quick-fit device is adapted to be activatedfor coupling a circumferential sector to said central body, byrelatively moving in a radial direction, said circumferential sector andcentral body close to each other.
 23. The apparatus as claimed in claim19, wherein each circumferential sector is adapted to be uncoupled fromthe central body by deactivating at least one reversible quick-fitdevice.
 24. The apparatus as claimed in claim 19, wherein eachcircumferential sector is adapted to be removably coupled to saidcentral body or uncoupled from the central body by activating orrespectively deactivating at least one reversible quick-fit device foreach circumferential sector.
 25. The apparatus as claimed in claim 20,wherein said reversible quick-fit device is a snap-fit device.
 26. Theapparatus as claimed in claim 25, comprising at least one releaseelement adapted to be relatively moved, in a radial direction, close tosaid circumferential sector coupled to said central body so as todeactivate said snap-fit device and uncouple the circumferential sectorfrom said central body.
 27. The apparatus as claimed in claim 25,comprising a snap-fit device for each circumferential sector.
 28. Theapparatus as claimed claim 25, wherein said snap-fit device comprises atleast two portions distributed along an axial direction of said centralbody.
 29. The apparatus as claimed in claim 28, wherein at least oneportion of the snap-fit device is disposed at an end portion of acircumferential sector in a coupled configuration with the central body.30. The apparatus as claimed in claim 25, wherein the snap-fit devicecomprises at least one movable hooking element adapted to take at leastone active position at which said snap-fit element is activated and apassive position at which said snap-fit element is deactivated.
 31. Theapparatus as claimed in claim 30, wherein said movable hooking elementis constantly biased to an active position.
 32. The apparatus as claimedin claim 30, wherein said movable hooking element is adapted to moveaccording to a substantially axial direction of the central body. 33.The apparatus as claimed in claim 30, wherein said movable hookingelement is associated with the central body.
 34. The apparatus asclaimed in claim 30, wherein the snap-fit device comprises at least onefixed hooking element comprising a housing seat adapted to receive saidmovable hooking element in the active position of the movable hookingelement.
 35. The apparatus as claimed in claim 34, wherein said movablehooking element and/or at least one portion of a confining wall of thehousing seat comprises a shaped outline adapted to allow relative movingapart of a circumferential sector associated with the release elementrelative to the central body.
 36. The apparatus as claimed in claim 34,wherein said fixed hooking element is associated with a circumferentialsector.
 37. The apparatus as claimed in claim 34, wherein said fixedhooking element comprises at least one ramp adapted to interact with themovable hooking element to produce shifting thereof from the activeposition to the passive position and cause introduction thereof intosaid housing seat, thereby activating said snap-fit device.
 38. Theapparatus as claimed in claim 25, wherein said snap-fit device comprisesat least one release element.
 39. The apparatus as claimed in claim 38,wherein the snap-fit device comprises at least one fixed hooking elementcomprising a housing seat adapted to receive said movable hookingelement in the active position of the movable hooking element, andwherein said fixed hooking element comprises a slide seat for saidrelease element, said slide seat being in communication with saidhousing seat.
 40. The apparatus as claimed in claim 39, wherein saidmovable hooking element is adapted to end in said slide seat in theactive position of the movable hooking element.